Understanding the optimal use of various therapies in life-long complex chronic diseases is vital to the present health care mission of maximizing health and minimizing costs. This K08 award proposal outlines a training and research plan to facilitate my development into an independent health services researcher focusing on the pharmaco-economics of complex chronic diseases. My main career goal is to apply health economics and decision science to inform health policy on the optimal use of various pharmaco-therapies. In the next five years, I will focus on the pharmaco-economics of biologic therapies in inflammatory bowel disease (IBD) (Crohn's disease [CD] and ulcerative colitis [UC]). Biologics are currently the most effective and most expensive therapeutic options in IBD. My project seeks to answer how biologic therapies have impacted the health and economics of IBD, and how biologics can be used more cost-effectively. This K08 award will help me accomplish the following training and career goals: (1) to acquire necessary skills in health economics and decision science to evaluate the pharmaco-economics of complex chronic diseases, (2) to become an independent health services researcher investigating the comparative cost-effectiveness of clinical strategies. To achieve these goals, I have assembled a mentoring team comprised of primary mentor, Dr. Jay Bhattacharya; co-mentor, Dr. Paul Wise; two advisors, Dr. Margaret Brandeau and Dr. Jeremy Goldhaber-Fiebert. Training will include formal courses and individual mentoring. The research goals in this proposal are motivated by the following question: Given the variety of therapeutic options and differences in IBD patient profiles, what is the best way to use biologics to sustain health and decrease costs? The project has three specific aims: Aim 1: To characterize the pharmaco-economics of biologics in CD and UC by determining the utilization trends and treatment effects on patient outcomes. Aim 2: To determine the cost-effectiveness of biologic therapies for biologic-naive CD and UC patients. Aim 3: To determine the health policy implications if optimal cost-effective treatment strategies were adopted in the use of biologics in CD and UC patients. I will address these aims through a large database analysis using econometric methods, two comparative cost- effectiveness analyses that compare biologics in head-to-head simulations, and two competing risk-analyses that elaborate health policy implications if cost-effective use of biologics were to become standard clinical practice.